Summary of thoracic computerized tomography findings. a Plain axial slices demonstrating a hyperintense crescent on the right margin of the aortic lumen indicating intramural hematoma (white arrow). b Contrast enhanced axial slices demonstrating the intimal flap (white arrow) that underlies the pathognomonic “double lumen sign”. c Volume rendered reconstructed image showing the margins of the Stanford type A aortic dissection (white arrow). The right coronary artery and the major thoracic and cervical arteries are not involved.